1. Field of the Invention
The present invention relates to an ink suitable for ink-jet recording and also to a recording method and apparatus using the same. In particular, the present invention relates to an ink that is capable of achieving highly detailed and high image quality recording not only on coated paper specially prepared for ink-jet recording, but also on non-coated and plain paper, such as paper for copying, paper for reporting, notepaper, letter paper, and bond paper or continuous slip paper, that is commonly used in offices and homes, and also to a recording method and apparatus using the same.
2. Related Background
Inks with greatly varying compositions have been hitherto reported with respect to inks for ink-jet recording. In particular, in recent years, detailed research and developments have been made from various approaches such as composition and physical properties so that a good record can be made even on a plain paper, such as paper for copying, paper for reporting, notepaper, letter paper, bond paper or continuous slip paper, as commonly used in offices. Such ink generally comprises an organic solvent with a high boiling point, such as glycols, for the purpose of anti-dryness and anti-clogging. However, in a case where a record can be made on a plain paper with high sizing degree using such an ink, ink cannot easily permeate into paper and the recorded portion cannot dry quickly. Therefore, there has been a problem in ink-fixing property such that hands become dirty when the recorded matter is touched, and letters are rubbed to become dirty.
Under such circumstances, in order to increase the permeation of ink into paper, Japanese Patent Application Laid-Open No. 55-29546 proposes a method in which a large amount of a surfactant is added in ink. In such an instance, the following problems have been caused: feathering occurs very frequently on some kinds of paper; when filled in an ink-jet recording head, the ink recedes from the orifice surface depending on the structural conditions of the head, resulting in no ejection of ink, or on the other hand, the whole of the orifice surface becomes wet, also resulting in no ejection of ink.
Japanese Patent Application Laid-Open No. 58-57862 proposes a method in which the pH of the ink is adjusted to the alkaline side. In this instance, however, there are disadvantages such that the ink is harmful when touched by hand or good results cannot be obtained in view of both feathering and drying performance when the ink is used on a paper that contains a certain kind of sizing agent, e.g., a neutralized paper. Besides the foregoing, various improvements have been attempted. Up to the present, however, no ink is known which can satisfactorily settle all the above problems with respect to feathering, drying performance and safety of ink, and also the problem of clogging.